Sand trap and filter for oil wells



July 8, 1941. L s, J, THQMAS 2,248,834

SAND TRAP AND FILTER FORv OIL WELLS ATTQRNEYS sheets-sheet 2 AAPZS.

S. J. THOMAS sARD TRAP AND FILTER FoR oIL wELLs Filed Jan. 22, 1940 AVAVAVAV l July 8, 1941.

S Y E N R O T T A WITNESS Patented July 8, 1941 SAND TRAP AND FILTER FOR OIL WELLS Stephen J. Thomas, Long Beach, Calif.

Application January 22, 1940, Serial No. 315,070

solaims. (c1. 16s-5) i My invention relates to new and useful improvements in oil well construction.

An important object of my invention is the provision in an oil well construction of a sand trap adapted to be disposed below the oil bearing stratum and within the outer casing of the well to receive the sand and other residuum carried into .the casing by the natural ow of the oil.

Another object of my invention is to associate the sand trap with the casing in a manner where-` by the same may be easily and expeditiously removed from the w-ell and the 'detritous emptied therefrom.

Still another object of my invention is the provision of an oil well construction of the abovementioned character wherein the flow line pipe is adjustable to permit the open lower end thereof to be positioned slightly above the. detritous in the trap at all times.

Yet another object of my invention is to provide an oil well construe-tion of the above-mentioned character wherein it will only be necessary to draw a relatively short section of the casing together with the sand trap in order to eiect a complete and efficient cleaning of the well and wherein no oil will remain in the casing section, and such quantities of oil as remain in Ithe trap may be easily and expeditiously emptied therefrom when the same is drawn to the surface.

A further object of my invention is the provi'- sion in an oil well of a sand trap that may be easily' applied to a conventional oil well construction and that is efficient and eilicacious in the performance of its duties. v Y Y A still further object of my invention is to provide an oil well construction thatv comprises telescoping .tubular sections uniquely associated to permit certain of the .sections to be withdrawn from the well independently of the other sections and wherein the length of' each of the sections is such as to require but Ia minimum length of section to be withdrawn in the practice of the'in-v Figure l is .a side elevation, showing parts' broken away, of the upper section of an oil well construction embodying my invention. Y

Figure 11A is a longitudinal sectional view of another section oi' my improved @il well construetion subjacent to the section illustrated in Figure 1, t

Figure 1b is a longitudinal sectional view of still another section of my improved oil well construc-` tion subjacent to the section illustrated in Figur la.

Figure -lc is a longitudinal sectional View of yet another section of my improved oil well construction subjacent to the section illustrated in Figure lbgand Figure 2 is an exploded perspective View' of an anchor or stop element embodying a part of my invention. Y

In the accompanying drawings, wherein for the purpose of illustration, is shown a preferred embodiment of my invention, the numeral Il) desig-V nates a conventional Christmas tree or manifold valve construction disposed at the surface of the ground above the well and surmounted by the usual plug or cap II. A'discharge branch 40 extends laterally of the Christmas tree, a control valve 4I is coupled therewith in the conventional manner to regulate 'the flow of oil therethroughand Ia pressure gauge 42 is connected to and communicative with the line 40 to 'register the hydrostatic pressure of the oil flowing therethrough. An `inlet conduit 82 is connected to the Christmas tree and includes a control valve183 and pressure gauge 84. The valve 83 controls the flow of uid through' the pipe into the manifold valve and the gauge 84 registers .the pressure-of the same. The base of the vvalve I Il is formed with an annular flange I2 to which the annular iiange I3, formed at the upper end of the casing I4, is secured by means of the bolts I5. The casing I4 extends downwardly to a pointv slightly above the upper surface of an oil bearing stratum andthe relative shortvhanger section I6 is attached thereto in longitudinal alignment therewith by the coupling I1. The upper end I8 of the hanger section is of the same diameter as the casing I4 an-d the lower end thereof is tapered' inwardly as at I9 Iand terminates in a cylindrical skirt portion 20. l

The foraminated casing 2| is of lesser diameterv than the casing I4 and is adapted to be lowered therethrough.` 'I'he upper end of the casing is screw-threaded, as at 22, to engage the internally screw-threaded lower end 23 of the companion hanger section 24. The middle portion of the hanger section 24 isr flared outwardly as at 25,'and the Vupper en-d thereof is of substantially cylindrical formation `and of slightly greater diameter than the -ared portion 26 lto define an external annular bead 26' but of lesser diameter than the internal bore of the casing |4. The inwardly tapered portion 2B of the male hanger section is provided with a peripheral groove 21 adapted to receive the sealing ring 23 which bears against the seat formed by the inwardly tapered portion I9 of the hanger section |6 to form a fluid tight union between the hanger sections. The tapered portion of the hanger section I6 is formed with an internal annular seat I9 adapted to engage the bead 26 of lthe hanger section 24 to effectively support the said hanger and the tubular sections carried thereby.

The upper level of the oil bearing stratum is designated by the numeral 23 in Figure 1a, and the lower casing 30 is secured'to the uppermost casing 2| in longitudinal alignment therewith .by the coupling 3|. The foraminated sections of the casings 2| and 33 extend through the oil bearing stratum, the lower level of which is designated by the numeral 32, and longitudinally aligning sections of vas many of the foraminated casings as are necessary to traverse the stratum are held together by the couplings 3|. The openings in the casings are 1 preferably diamondshaped and are spaced annularlytherearound, as clearly shown in Figures la, 1b, and 1c.

The forarninated'sections terminate at the bottom'level 32 ofthe oil bearing stratum and the solid tubular casing 33 is secured thereto in longitudinal alignment therewith by the coupling 4 3|; The casing 33. may be'of any desired length,

preferably extending for a considerable distance below the lower level of the oil stratum and has a female hanger section 34secured to the lower endthereof by a coupling 3|. The upperend y35 of the hanger sectionis of 'the same diameter as the casing33* and tapers inwardly therebelow, as at 36, which portion terminates in a depending annular skirt 31. o

YTh'erow line pipe 3B is suspended from the plug by means of the transverse pin 39 and extends through the sections of the casingA and into the section 33 below the lower level 32Y of the oil'bearing stratum. VThe pipe is adapted'tocon'- vey the oil to the surface of the ground and is therefore connected with the discharge pipe 43;'

' A foraminated liner section 43, of slightly lesser diameter than the foramihated casing 30, is disposed within the casing` 33' and extends between the upper and lowerA levels of the voil lbearingistratum. The apertures in the liner'43 arein the form of elongated slots, ande-are preferably larger than the'aperturesin'the outer casing' 30 to assure a free and unrestrained flow of oil therethrough. The foraminated `liner section terminates at the lower level-32 of the stratum and a plain tubular section-44, comprising a-sand trap, is connected thereto in longitudinal alignment therewith by' the coupling45. The lower end 4Bof the plain liner 44 is similarly connected to the male hanger section 41--by acoupling 45. Thev hanger section is tapered inwardly as at y48 adjacent the lower end thereof and the tapered portion terminates in a cylindrical apron 49, the lower end of which is externally screw-threaded to receivethe cap A5|?.V The cap is formed with a centralinlet stem 5| surmounted by aconical shaped 'cover provided Ywith a pluralityofradia-lly disposed'slots 53. The stem 5|' is formed with a central bore 54`which affords communieation with the sand trap through the cap 5|).`

The upper'erldI of the foraminated liner 43 terminates at a point'slightly below the upper level 230i the oil bearing stratum and isexternally iscrewthreaded to receive the lockhead 55.

The inner bore of the lockhead curves inwardly, as at 56, to define a substantially upper thick collar 51 disposed in abutting relation with the lower annular iiange 58 of the gooseneck 59. The gooseneck preferably comprises companion shells or sections adapted to be applied at opposite sides of the ow line pipe and to be held together by bolts 59', or the like. The lower flange 58 of the gooseneck is provided with a plurality of spaced annular openings through which the bolts 63 are inserted to engage aligning openings in the collar 51 of the lockhead. An oil diverter 6| comprises a cap surmounting the upper end of the gooseneck ,and having a sliding iit with the flow line pipe. The'oil diverter is also preferably made of split sections which permit the same to be easily applied to the pipe and, when assembled, prevent oil from flowing along the outer surface of the pipe and through the gooseneck 59.

Guards 62 are mounted at spaced intervals along the foraminous liner 43 and comprise spaced collars 63 and 64 Xedly associated with the linerY and connected by a plurality of spaced outwardly bowed resilient webs 65. The webs 35 have a light frictional engagement with the inner periphery of the casing and hold the liner concentrica'llyv disposed therein.

An' oil ring and scraper 66 is carried by the liner 43 adjacent the lower extremity thereof. The ring comprises an.. annular section B1 encirclingr the liner slightly below the lowermost openings; the section` 61 having an outwardly fiared upper portion l Biadapted to frictionally engage the inner wall of the outer casing V3&3. A collar 69 encircles the lower portion of the ring to hold the same fixedly attached to the liner.

Guards 10 are similarly disposed at spaced intervals along the flow line pipe 38 and similarly comprise spaced collars 1|k and 12 xedly associated with the pipe and integrally connected by a plurality of spacedV outwardly bowed resilient webs: 13'which engage the inner periphery of the liner'43 tohold the flow line pipe concentrically disposed therein.

Anz'anchor or stop element 14 is carried by the iiow line pipe a substantial distance below the gooseneck 59, which distance should correspond roughly tothe length of the sand trap 44 for reasons hereinafter set forth: They anchor 14 comprises'hemicylindrical companion shell sections 15 and 16provided Ywith registering axial grooves111 and 18, respectively. Shell section 15 is provided with a plurality of tapped openings 19 adapted to register with thev openings 8l) in the shell section 13 and to receive the threaded ends ofthe bolts 3|. The anchor is preferably constructedin sections' to permit'the same to be easilyapplied to the iiow line'pipe and to be easily adjusted thereon; and the bolts 8| may be tightened to movethesections towardV each other and into close frictional engagement with the said pipe.y f A second stop or anchor 14 is similarlyv disposed a substantial distance above the gooseneck.

MyA invention-is particularly adapted to Vprevent'the well from-being rendered inoperative by the accumulation of sand in the lower portion thereof. The outer casing I4 is first lowered into thewell -until the lower end' thereof ispositioned slightly above the upper level of the oil stratum. The lower end is thenfcemented and a hole drilled intheI cement throughA which the slightly/.smallerY casing 2| together with the foraminatedy sections 3|) and Asand trap 44 maybe dropped; The sections Sli-are lowered through the section |4 until the male hanger section 24 seats on the inwardly tapered section I9 of the female hanger section I6, illustrated in Figure la. The liner sections 43 and 44 connected to the iiow line pipe 38 are then lowered 'through the casing. The lower stop 14 will engage the bottom end of the gooseneck 59 to hold the liner sections suspended from the iiow line pipe as the liners are lowered into the well and the resilient action of the guards 62 will guide the liner in its travel to prevent the casing from being damaged. The male hanger section 41 suspended from the lower end of the sand trap will seat on the inner Vface of the inwardly tapered portion 36 of the female hanger section 34, and thereafter the flow line pipe may be lowered to position the open end of the same slightly above the stem I.

The stem 5I will permit any oil which has collected at the bottom `of the casing 33 to ow into the sand trap, thus obviating the possibility v of the oil preventing the trap from being lowered the desired distance. 'I'he stop 14 carried by the ow pipe above the gooseneck will engage the upper end of the gooseneck to force the liner and sand trap along the casing, if necessary.

Thecasing I4 may extend for several thousands of feet below the surface of the ground to the upper surface of a stratum of oil bearing sand. 'I'he length of Vthe foraminated casing and liners will, of course, be governed by the depth of the stratum of sand and Vthe sand trap may extend several hundred feet below the oil bearing sand.

'Ihe oil in the sand may ow through the diamond-shaped foraminations in the casings 2| and 30 and through the elongated slots in the foraminous liners 43. The oil rings and Scrapers 56 disposed at spaced intervals along the fora-minous lining 43, by reason of the frictional engagement thereof with the inner periphery of the casing, will collect the oil iiowing down the inner wall of the casing and direct the same through the slots in the liner 43 and into the sand trap 44. The inow of oil through the casing will carry slight quantities of sand therewith. As the oil iiows through the liner and into the sand trap, the sand and other detritous will settle to the bottom of the trap and the oil will lill the portion of the trap above the sand. The adjustable feature of the ow line pipe which permits the same to move independently of the liner for a limited distance, permits the open lower end thereof to be spaced slightly above the accumulating sand in the sand trap at all times and to convey the oil to the surface by pressure or pumping methods.

The foraminations in the outer casing 30 are preferably diamond-shaped for the reason that thesand carried by the oil flowing therethrough will tend tol collect and pack in the openings, thus preventing the free flow of oil therethrough. However, by using the diamond-shaped perforations the sand will not collect therein to such a marked degree due to the fact that the centeror middle part of the diamond-shaped opening is wide and tapers to a point at both ends. This enables a deposit of sand collected therein to be broken away very easily and with a minimum amount of suction.

When the sand trap becomes full or substantially full and the flow line pipe has been elevated to a position where the lower stop 14 engages the bottom of the gooseneck 59, it will be necessary to pull the perforated lining 43, together with the sand trap, from the well and during this operation water, oil or other fluid is pumped into the well through the inlet conduit 82 to maintain the ,oil and gas pressure of the well. The fluid need only'to be` pumped 'inte the casing and it is not necessary that the same be pumped into the oil sand, thus making it unnecessary to disturb the oil sand structure. After the well is filled with oil, or other fluid, the liner and sand trap may be pulled tothe surface by any suitable means vand. the sand and other detritous emptied from the trap and new sections substituted for old or worn ones. 'I'he operation of removing the'liner and sand trap is easily accomplished within a very short time and the unit can be pulled up-at any time for cleaning or inspection. The oil rings and scrapers 66 frictionally engage the inner bore of the casing and scrape and clean the surface of the same when the liners and sand trap are being drawn from the casing.

In the event that the flow line pipe 38 should break, an over-shot tool may be secured to the end of the drill pipe and lowered into engagement with the gooseneck. The lock ofthe tool may then be released to cause the same to engage with the gooseneckto permit-the liner'and sand trap to be drawn to the surface. After the trap has been thoroughly cleanedand any necessary portion thereof repaired, the liner and trap may be lowered into the well, the oil or water previously pumped into the well may be removed by a pumping or swabbing operation and pumping operations resumed. It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the size, shape'and arrangement of parts may be resorted to without departing from the spirit of my invention, or scope of the appended claims.

Having thus described my invention, I claim: l. In an oil well construction, a sand trap comprising anl impervious tubular casing adapted to be disposed below the oil bearing strata; and an impervious tubular liner of lesser diameter than the lcasing disposed concentrically in the casing and being entirely enclosed thereby, the lower end of the said liner having a sealed engagement with but not connecting lto the casing and having an open top to permit passage of a uid therein and a perforate bottom to permit fluidin the casing to have access into the liner when the lower end of the same is lowered into engagement with the casing.

2. In an oil well construction, a sand trap comprising kan impervious tubular casing adapted tov be disposed below the oil bearing strata, an impervious tubular liner of lesser diameter than the casing disposed concentrically in the casing and being entirely enclosed thereby, the lower e'nd'of the said liner engaging but not connecting with the casing having an open top to permit passage of a fluid therein and a perforate bottom to permit fluid in the casing to havel access into the liner when the lower end of the same is moved into engagement with the casing, and oil rings girdling the liner and engaging the contacted surface of the casing to form a fluid-tight union' therewith.

3. In an oil well construction, a sand trap comprising an impervious tubular casing formed with a constricted lower end, an impervious tubular liner disposed concentrically within said casing for substantially its entire length and with the lower end thereof supported by but unconnected with the constricted lower end` of the casing and a flanged collar girdling the upper end of the liner and extending obliquely therefrom to wip ingly engage the inner wall of the casing to prevent foreign particles from having access to the space between the liner and casing.

4. In an oil well construction, a foraminous tubular casing adaptedto extend through an oil stratum and to terminate at its upper and lower levels, a plain tubular casing connected tothe lower end of the first casing and adapted to extend a substantial distance below the oil stratum, a foraminous tubular liner coextensive with the first foraminous casing, and in circumferentiallyspaced relation therewith in a manner to be readily removable therefrom, and a plain tubular liner comprising a sand trap connected to the first liner and extending into the plainv casing, the said last liner being supported by but not connected to the said plain casing in a u manner to be removable with the said foraminated liner.

5. In an oil well construction, a foraminous tubular casing adapted to extend through an oil stratum and to'terminate at its upper and lower levels,v a plain tubular casing connected to the lowerl end of the rst casing and extending a substantial distance below the oil` stratum; a foraminousy tubularY liner coextensive with the rst foraminous casing and in circumferentially spaced relation therewith whereby to be readily removable therefrom, avplain tubular liner having a closed bottom end and comprising a sand trap connected tothe lower end of the nrst'liner and extendinginto the plain casing, the last-mentioned liner being supported by but not'connected to the plain casing whereby to be removable with the said foraminated liner, and a collar girdling the upper end of the plain liner and wipingly engaging the inner wall of the plain casing to direct solid particles entering the foraminations of the flrstvcasing into the said sand trap.

6. In an oil well construction, the combination of a foraminous tubular casing adapted to extend through an oil stratum and to terminate at its upper and lower levels, a foraminous liner concentrically disposed within and'circulnferentially spaced from said casing, an impervious casing connected tothe lower end of the foraminated casing, an impervious liner connected to the lowerend of the foraminated liner and extending ing, an oil conduit concentrically disposed within said liners andr being freely axially movable therein,vr a collar slidable on the oil conduit and nxedly connected to the upper end of the-liner, and stop means fixedly carried by the'oil conduitJ above and below the collar and being nspaced apart a sufficient distance to permit the Alower end of the conduit to travel the full length of the impervious liner, the said lower stop means being uniquely adjusted to engage the collar upon upward movement of the conduit to move the said liners upwardly therewith. 1

7. In an oil well construction, the combination of a foraminous tubular casing adapted to extend through an oil stratum and to terminate at its upper and lower levels, a foraminous liner concentricallydisposed within and circumferentially spaced from saidV casing, an impervious casing connected to the lower end of the foraminated casing, an oil conduitl concentrically disposed within said liner and being'freely axially movable therein, a collar slidable` on the oil conduit and connected to the upper end of the liner, a sand trap carried by and disposed below the liner and adapted to receiveV the` lower end yof the oil conduit, and astop means fixed to the conduit above and below the collar and being spaced apart a sufficient distance/to permitthe lower end of the conduit to travel thel full length of the said trap, the said lower stop means 'being uniquely adjusted to engage `the collar during the upward movement of the conduit to elevate both the said liner and trap.

8. An oil well construction comprising an outer casing extending from the ground surface to a point substantially below the bottom level of an oil bearing strata, said casing being impervious except for a perforated section extending between the upper and lower levels of the strata; an inner liner freely axiallyTr movable within the casing and extending from the'upper level of the strata to the lower end of the casing, the portion of the liner extending through the oilbearing strata being perforated and the portion thereof extending below the strata being impervious and comprising a sand trap; and a collar encircling the liner at the juncture of theperforated and impervious sections, the said collar having a peripheral wiping engagement with the inner periphery of the casing to direct foreign particles entering the perforated sections of the casing and liner into the said sand trap.

9. An oil well construction comprising an outer casing extending from the vground surface to a point substantially below the bottom level of an oil bearing strata, said casing being impervious except for a perforated section extending between the upper and lower levels of the strata; an inner liner freely axially movable within the casing and extending from the upper level of the strata to the lower end of the-casingthe portion of the liner extending through the oil bearing strata being perforated and the portion thereofV extend ing below the strata being impervious and comprising a sand trap; a collar encircling the liner at the juncture of the perforated and impervious sections, the said collar'havinga peripheral wiping engagement with the innerperiphery of the casing to direct foreign particles entering' the perforated sections of the casing and liner into the saidA sand trap; an oil conduit extending from the ground surface and through the liner; and

coupling means connecting the oil conduit to the liner but permitting the conduit to have a limited independent axial movementV within the liner suflicient to permit the lower' end of the conduit to travel the entire length of the sand trap whereby positioning the conduit at the upper limit of its independent travel will render the coupling means operativeA and whereby vfurther elevation f of the conduit will move the liner axially withinv the said outer casing.

- STEPHEN J. THOMAS. 

